Exhausting Critical
Your critical hits cause opponents to become exhausted.
Prerequisite: Critical Focus, Tiring Critical, base attack bonus +15.
Benefit: When you score a critical hit on a foe, your target immediately becomes exhausted. This feat has no effect on exhausted creatures.
Special: You can only apply the effects of one critical feat to a given critical hit unless you possess the Critical Mastery feat.
Source: Pathfinder Core Rulebook, p. 123